A Novel Alternative Infrastructure for Efficient High
Volume Computation
Pouya Dianat, Zhihuan Wang , Thinzar Aung , Mark Hempstead , Loannis
|
Savidis , Baris Taskin , Marc Currie, and Bahram Nabet,
1
1
1
1
1
2
1
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1Electrical
and Computer Engineering Department, Drexel University, Philadelphia, PA 19104, USA
2Optical Sciences Division, Naval Research Laboratory, Washington, DC 20375, USA
Introduction
Abstract
Recently, the analysis of big data has become the engine for societal,
financial, scientific, and technological endeavors. This demands an
infrastructure that is capable of fast and reliable high volume data
processing. Here a monolithic nano system is proposed for low energy
computations. It functions based on optically connected one dimensional
solid state devices. This design circumvents the electron-transport limitations
of conventional technologies, offers innate integration of optics and
electronics,
and
applies
novel
physics
of
one
dimensional nano structures and many-electron systems. Overall, this
alternative technology can reduce the energy cost per unit of computation
and increase the rate of reliable data transfer.
(b)
Energy Consumption in Data Centers
Meeting
the
energy
needs
of
the
communication of information, together with
storage and computation form a “grand
challenge” of the information age.
Data centers currently consume 1.5% of global
energy production, and up to approximately
4% of U.S. energy produced. Though the
statistics seems small, a 1000 times increase
in the volume of data is predicted by 2025.
Google data center alone consumes enough
electricity to power 200,000 homes, since an
average Google search or a YouTube video or
a message through Gmail uses 0.3 watt-hours
of electricity. Having efficient data computation
tools will greatly reduce the 59% of the total
data center power consumption into a greener
number.
(a)
Lighting
2%
Distribution
8%
(c)
Cooling
31%
Data Computation
59%
1 µm
 (a) Intel Ivy Bridge ® 22nm microprocessor layout illustration.
 (b) ~30% to 55% of the light is reflected in bulk Si and GaAs/AlGaAs core-shell
nanowire, with a sharp change for wavelengths near band gap.
 (c) Only ~2% to 6% of light is reflected by GaAs/AlGaAs core-shells are grown on top of
Si substrate, with the spectrum showing clearly that reflection is from wires not Si.
 The same enhancement (~900 times compared to bulk) also observed in emission.
Role of Dimensionality
Scanning Electron Microscopy (SEM) image for
GaAs/AlGaAs core-shells grown on Si substrate; 45
angle view. Inset is magnified view showing facets
and top tapering of core-shells grown on Si.
Room
temperature
micro-photoluminescence
spectra with increased pump power shows multimode lasing above threshold. Emission amplitude
depends on intensity of the excitation light.
Using the collective response of electron and hole gasses confined in
reservoirs which operate near quasi-equilibrium conditions, hence
consuming little power.
•
Confinement in low dimensionalities can significantly alter electronic and
optical properties of the Charge Carriers in our novel infrastructure. In
response to short optical pulses, our device produces electrical pulses
which are almost 100 times faster than the same device without the
charge reservoirs. In terms of lasing, our devices achieved nearly 10,000
times more brightness in these wires compared to thin-film.
•
Joint optical density of state (JODS), 𝑁𝑁𝐽𝐽 (𝓔𝓔) , is a strong function of
dimensionality:
𝑁𝑁𝑗𝑗3𝐷𝐷
With increasing demand for ultra-small, high-speed and highly
efficient integrated photonics circuits, the nanowire optical devices
play an important role either as coherent light source or in optical
communications for intra-chip and inter-chip interconnects.
(a)
•
=
1 2𝑚𝑚𝑟𝑟∗ 3⁄
( 2) 2
2
2𝜋𝜋
ℏ
ℏ𝜔𝜔 − 𝐸𝐸𝑔𝑔
1⁄
2
𝑁𝑁𝑗𝑗2𝐷𝐷
=
𝑚𝑚𝑟𝑟∗
𝜋𝜋ℏ2 𝐿𝐿𝑧𝑧
𝑁𝑁𝑗𝑗1𝐷𝐷
=
3
𝑚𝑚𝑟𝑟∗ �2
𝜋𝜋𝜋𝑚𝑚𝑒𝑒∗ 𝐿𝐿𝑥𝑥 𝐿𝐿𝑦𝑦
𝟏𝟏
(ℏ𝜔𝜔−𝐸𝐸𝑔𝑔 )
330 nm
(c)
Conclusion
(b)
Spatial distribution of the free-electron gas with
high doping density in the GaAs/AlGaAs coreshell nanowire. The core-shell nanowire has
unique 1D pillars of charge at the corners, and
2D at the facets when the doping density is high.
1 µm
The longitude mode (c) of
hexagonal core-shell nanowire
with Si substrate for 25 degree
1 µm of light incident angle. The
three electric field maximums
centered at each facets of the
Hexagon with tilted angles, and
demonstrated light reflection
inside the nanowires along the
grown axis and build up the
longitude
standing
wave
patterns.
An FDTD-simulated electric field profile
Electronics faster than speed of electrons and (linear scale) shows a hexagonal mode
with less energy. Charge plasma confined in a pattern (TM
12n ) in the transverse plane (a)
semiconductor can transfer energy, hence
respond much faster than the carrier drift current. and longitude plane (b) of a single
hexagonal
GaAs/AlGaAs
core-shell
nanowire with normal incident light.
Nanowires show extremely enhanced electronic and optical
properties. Our vision is to build upon novel optoelectronic devices
capable of computing a bit while consuming attojoules of energy, and
progress to energy efficient methodologies for electronics that
consume terawatts of power.
Reference
1. Z. Wang, M. Currie, P. Dianat, G. Konica, P. Prete, N. Lovergine, et al.,
"On Dimensional Dependence of Interaction of Light and Nano
Structures," in Frontiers in Optics, Orlando, FL, 2013.
2. P. Dianat, A. Persano, F. Quaranta, A. Cola, and B. Nabet, "Anomalous
capacitance enhancement triggered by light," IEEE J. Selected Topics
in Quantum Electronics, Vol. 21. No. 4, 3800605, 2015.
3. B. Nabet, M. Currie, P. Dianat, F. Quaranta, and A. Cola, "High-Speed
High-Sensitivity Optoelectronic Device with Bilayer Electron and Hole
Charge Plasma," ACS Photonics, 2014.
(a)
 (a) Capacitance-Voltage characteristics under various illumination
intensities for MSM-2DHS capacitor. There is a 43 times capacitance
enhancement for under illumination compared to dark measurement. This
is mainly due to an increase in the population of the 2DHS by light-generated
carriers.
 (b) Time response to ~400 fs light pulses with 54 μW optical power, at 0
(black), 1 (red) and 2 (blue) V bias. Inset is normalized to the peak showing
2.9, 2.9 and 2.5 ps full-width at half-max (fwhm) pulse width, respectively, for
the device with > 8.5 μm gap distance between the cathode and anode.